Investments (Borrowed Securities Repurchased Securities And Repurchased Reversed Repurchased Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Securities Sold under Agreements to Repurchase	$ 0	$ 92,446
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	0	107,158
Securities for Reverse Repurchase Agreements	442,679	298,466
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	484,751	338,929
Reported Value Measurement [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Borrowed	265,240	201,050
Estimate of Fair Value Measurement [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Borrowed	281,225	212,946
Securities for Reverse Repurchase Agreements	$ 468,008	$ 314,160